Infrastructure for solar physics: the Swedish 1-m Solar Telescope (SST)

The Institute for Solar Physics (ISF) was established by VR at Stockholm University as a Research Infrastructure of National Interest on 1 January 2013.

ISF operates the Swedish 1-m Solar Telescope (SST) at 2400 m altitude on La Palma, Spain.SST is world-leading in terms of image quality since its inauguration and ISF staff has systematically developed instrumentation to fully exploit the scientific potential of SST.

These developments target the “big” questions of future solar physics, which is to understand the heating and dynamics of the hottest layers of the solar atmosphere: the chromosphere and transition layer to the corona. The most powerful instruments for such studies are CRISP (installed 2008) and CHROMIS (installed 2016).

A third instrument (HeSP) for studying magnetic fields in the uppermost chromosphere will be installed in 2021.

This application contains a plan to replace CRISP with a new instrument called CRISP2 that will have a three times larger field of view.SST has given rise to many publications in Nature and Science and has a unique potential for answering some of the most important questions in solar physics.

Its scientific value is further evidenced by the fact that ISF sells around half of the available observing time to international users in Norway, Germany, and the USA.

SST is a world-leading facility of crucial importance for European solar physics until the European Solar Telescope (EST) is in operation in 2029.

Funding of ISF is requested for continuing operations at a level similar to now for the period 2022-2027, including observations for 200 days per year, operation of a data center, and continuous improvement of the instrumentation and data reduction algorithms.